Humans. Humans can learn some mathematics and probability theory to improve their strategic play, and they’re able to become proficient at reading subtle cues in their opponents body language and facial expressions which may also provide information about the strength of their hands. Humans also have dextrous and nimble hands which may hold the cards without accidentally dropping them or crumpling them.

Most other animals will simply be too dumb to even know what the card values are, let alone learn the rules of any variant of poker.